A computer network is a geographically distributed collection of nodes interconnected by communication links and segments for transporting data between end nodes, such as personal computers and workstations. Often, the communication links comprise an optical link/fiber medium that may be used to digitally transfer light (optical) signals between the nodes to thereby relay information between the nodes, such as for optical lightpaths, synchronous optical networks (SONET), etc., as will be understood by those skilled in the art. Accordingly, optical link troubleshooting and monitoring are significant aspects of many network operations (e.g., particularly for service provider “Metro Ethernet” designs in which long-haul connections are present). For example, when a computer network (or portions thereof) is originally established, a network administrator may wish to know the optical link/fiber characteristics, such as a distance/length of the fiber, optical power loss (“link loss”) along the fiber, etc. Also, during operation of an optical network, problems may occur, such as communication failures/delays/etc. As such, it may be particularly beneficial to determine whether a problem is caused by a physical factor of the optical links (Layer-1), or by some other factor that is not physical, such as various protocol errors, software errors, applications errors, etc. (e.g., upper layers, Layer-2 through Layer-7), as will be understood by those skilled in the art.
Currently, various tools and mechanisms are available that may be used for optical link troubleshooting and monitoring. For instance, one set of tools currently available includes manual tools, such as an optical time domain reflectometer (OTDR). For example, an OTDR may be used by a technician to scan a fiber to determine its physical (optical) characteristics, such as link loss, locations of connectors/splices, length, etc. Such manual tools, however, are often expensive, require physical local access by a technician to use, and are not generally available in real-time at each location within the optical network. In other words, a technician needs to go to the site of the node, such as a network device, of interest for an original installation and/or in the event a problem occurs in order to diagnose any optical characteristics (which, notably, may have corrected themselves before the technician is able to reach the network device).
As another tool for monitoring and troubleshooting optical networks, certain networks may employ the use of a high-end (e.g., expensive) optical monitoring system that requires a centralized monitoring/supervisor system. For example, optical devices employed in conjunction with such systems may collect optical power information using a dedicated photo detector on the optical fibers (which “steals” light/power from the fibers), and may transmit this information to the centralized monitoring system. The centralized monitoring system processes the information received from the optical devices to, e.g., determine various optical quality parameters/characteristics generally used by network administrators for network management, maintenance, and configuration.
Each node or device within the optical network (that is, not including the centralized management system), however, is generally unable to compute optical quality parameters that require knowledge other than what may be measured on each device itself (e.g., its transmit power and its receive power for given fibers/links). As such, optical network devices are thus not conventionally configured to respond to optical (physical) quality parameters themselves. There remains a need, therefore, for an efficient technique for monitoring of optical characteristics, such as optical quality parameters and degradation, at each node within the optical network without the need for a centralized management system. In particular, there remains a need for such an optical monitoring technique that is dynamic, low cost, and available on-demand.